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The Influence of Dietary Fiber on Digestibility, Rate of Passage and Gastrointestinal Fermentation in Pigs
Abstract
Summary Twenty mature Yorkshire pigs were fed diets containing coarse bran, fine bran, alfalfa or cellulose (Solka floe) and the effects of these sources of fiber on large intestinal microflora, digestibility and rate of passage were investi- gated. An in vitro batch microbial culture system was used with fecal, cecal, upper large intestinal and lower large intestinal inocula to measure cell wall indigestibility and VFA production with the same (above) sources of fiber. In this system, composition of fiber that the pigs were consuming had a significant effect on cell wall indigestibility and VFA production. The quantities of VFA produced in vitro were significantly affected by composition of the substrates. The VFA concentrations in fresh feces were significantly affected by the dietary fiber consumed. The VFA concentrations were lower (P
... Hofmann [1989]. Food would then pass through the rumen faster and the acid stomach would have more influence on the hemicellulose than it does in larger ruminants [Ehle et al., 1982; Keys et al., 1970]. Although only the brockets digested significantly more hemicellulose than cellulose, the other three species digested both fiber fractions equally. ...
... The apparent lignin digestibility seen for pudu, brocket, and Maxwell's duikers in this study probably did not really reflect the digestion of lignin, but rather that during the process of chewing and digestion lignin was fractured down to a fine powder. During the fiber analysis procedure a coarse-porosity Gooch crucible is normally used, through which the fine lignin particles in the feces may easily pass, escaping detection (Van Soest, personal communication) [Ehle, 1982; Foley and Cork, 1992]. Once again, however, the bay duikers varied dramatically from the other species; the negative digestion coefficient for lignin indicated that a lignin-like artifact accumulated in the feces. ...
... Theoretically each digestive compartment is capable of selective retention. Pigs produce a distinct secondary peak that has been shown to be the result of cecal emptying [Ehle et al., 1982]. The Maxwell's duiker's higher metabolic fecal nitrogen (MFN) losses may come from microbes active in the lower tract, in the secondary points of retention, which therefore escape digestion and are lost in the feces. ...
Small ruminants are generally classified as either browsers or frugivores. We compared intake and digestion in one browsing species, the pudu (Pudu pudu), body weight 9 kg, and three frugivorous species, the red brocket (Mazama americana), 20 kg, the bay duiker (Cephalophus dorsalis), 12 kg, and Maxwell's duiker (C. maxwellii), 9 kg. Rations comprised: a commercial grain and alfalfa pellet, a small amount of vegetables, and mixed hay. Across species, neutral-detergent fiber (insoluble fiber) consumed averaged 34.2 ± 2.6% of dry matter (DM) while the crude protein consumed averaged 16.1 ± 0.5% DM. Apparent DM digestion was similar in pudu (75.2 ± 4.7%), brocket (73.2 ± 1.1%), and Maxwell's duikers (73.0 ± 2.8%), and significantly lower (P = 0.0167) in bay duikers (67.1 ± 4.3%). There were significant differences among species in digestibilities of neutral-detergent fiber, hemicellulose, and cellulose, but they did not follow body size differences, since larger species were expected to show higher digestion coefficients for fiber compared to smaller species. The type of fiber fed may have influenced these results. Frugivores may be adapted to a diet of soluble fibers, as might be found in wild fruits, instead of the insoluble fibers in the diet fed. Passage trials were conducted on the two smallest species. The mean transit time for pudu was 29.9 ± 0.8 hr, and for the Maxwell's duiker was 42.2 ± 6.4 hr. © 1996 Wiley-Liss, Inc.
... High levels of dietary fiber could decrease the digestibility of energy and nutrients in sows and growing pigs and have the potential to diminish the digestion efficiency (Le Gall et al., 2009) [7]. This may be because dietary fiber can reduce the exposure time of digesta to enzymes and hindgut microbiota, increase the passage rate of the nutrient flow, and have a significant influence on the large intestinal turnover (Ehle et al., 1982;Serena et al., 2008) [21,22]. Pigs cannot reach their full digestive potential when consuming fiber-rich ingredients, as the digesta would be excreted from the hindgut before it has fully been fermented, especially for adult sows fed a restricted diet. ...
... High levels of dietary fiber could decrease the digestibility of energy and nutrients in sows and growing pigs and have the potential to diminish the digestion efficiency (Le Gall et al., 2009) [7]. This may be because dietary fiber can reduce the exposure time of digesta to enzymes and hindgut microbiota, increase the passage rate of the nutrient flow, and have a significant influence on the large intestinal turnover (Ehle et al., 1982;Serena et al., 2008) [21,22]. Pigs cannot reach their full digestive potential when consuming fiber-rich ingredients, as the digesta would be excreted from the hindgut before it has fully been fermented, especially for adult sows fed a restricted diet. ...
This study was conducted to determine and compare digestible energy (DE) and metabolizable energy (ME) values and the apparent total tract digestibility (ATTD) of energy and nutrients in eight ingredients fed to both growing pigs and sows. Two experiments with 48 crossbred barrows or six non-pregnant sows were allotted to eight treatments in a completely randomized design or a pseudo Latin square with six replicated pigs per dietary treatment. The dietary treatments were formulated with two cereal ingredients: corn and wheat; two ingredients with a high protein level and a low fiber level (HPLF): soybean meal (SBM) and cottonseed meal (CSM); two ingredients with medium protein level and medium fiber level (MPMF): corn distiller’ dried grains with solubles (DDGS) and corn germ meal (CGM); and two ingredients with a low protein level and a high fiber level (LPHF): wheat bran (WB) and palm kernel meal (PKM), respectively. Adult sows had greater DE and ME values and ATTD of energy and nutrients when fed cereal ingredients compared with growing pigs, and had lower DE and ME contents and ATTD of energy and nutrients except for acid detergent fiber (ADF) when fed HPLF ingredients compared with growing pigs. Moreover, no differences were observed between adult sows and growing pigs in DE and ME contents and ATTD of energy and nutrients when fed MPMF and LPHF ingredients, except that adult sows showed a greater ATTD of crude protein (CP) when fed MPMF ingredients compared with growing pigs. Our results indicate that sows had a lower available energy and nutrient digestibility when fed SBM or CSM compared with growing pigs. Crude protein contents in ingredients should be considered when predicting DE and ME values in sows based on the DE and ME values measured from growing pigs.
... We also chose to sample pigs at the same time each day to eliminate any confounding effects relative to diurnal variation in fecal composition that has been previously reported [12,26,27]. Numerous experiments have been conducted to describe the time of first or 5% marker appearance [4,5,11,28], mean transit rate [6,8,[28][29][30][31] or 25, 50, 80, or 95% of the marker excreted [4,5,7]; values which are useful in mathematical modeling of digestion [3]. This was not the focus of our experiment as we chose to only determine when P2 fecal Cr reached its minimum LOQ and when P2 fecal Ti reached 95% of its maximum because we were interested in if the previous or present diet affected when a dietary marker was completely excreted (Cr, Table 3) or stabilized (Ti, Table 4). ...
... We also chose to sample pigs at the same time each day to eliminate any confounding effects relative to diurnal variation in fecal composition that has been previously reported [12,26,27]. Numerous experiments have been conducted to describe the time of first or 5% marker appearance [4,5,11,28], mean transit rate [6,8,[28][29][30][31] or 25, 50, 80, or 95% of the marker excreted [4,5,7]; values which are useful in mathematical modeling of digestion [3]. This was not the focus of our experiment as we chose to only determine when P2 fecal Cr reached its minimum LOQ and when P2 fecal Ti reached 95% of its maximum because we were interested in if the previous or present diet affected when a dietary marker was completely excreted (Cr, Table 3) or stabilized (Ti, Table 4). ...
Background
Indigestible markers are commonly utilized in digestion studies, but the complete disappearance or maximum appearance of a marker in feces can be affected by diet composition, feed intake, or an animal’s BW. The objectives of this study were to determine the impact of previous (Phase 1, P1) and current- (Phase 2, P2) diet composition on marker disappearance (Cr) and appearance (Ti) in pigs fed 3 diets differing in NDF content. ResultsWhen pigs were maintained on the 25.1, 72.5, and 125.0 g/kg NDF diets, it took 5.1, 4.1, and 2.5 d, respectively, for Cr levels to decrease below the limit of quantitation; or 4.6, 3.7, or 2.8 d, respectively, for Ti to be maximized. These effects were not, however, independent of the previous diet as indicated by the interaction between P1 and P2 diets on fecal marker concentrations (P < 0.01). When dietary NDF increased from P1 to P2, it took less time for fecal Cr to decrease or fecal Ti to be maximized (an average of 2.5 d), than if NDF decreased from P1 to P2 where it took longer for fecal Cr to decrease or fecal Ti to be maximized (an average of 3.4 d). Conclusions
Because of the wide range in excretion times reported in the literature and improved laboratory methods for elemental detection, the data suggests that caution must be taken in considering dietary fiber concentrations of the past and currently fed diets so that no previous dietary marker addition remains in the digestive tract or feces such that a small amount of maker is present to confound subsequent experimental results, and that marker concentration have stabilized when these samples are collected.
... Three piglets from each treatment group were selected to determine the rate of digesta passage at the end of the trial. The measurement of chime mean retention time (CMRT) in this study was performed according to the methods described by Ehle et al. (1982). Chromic oxide (0.2 g, Cr 2 O 3 ) was mixed into 99.8 g of feed and then fed to piglets once. ...
... The first fecal samples were collected 8 h after the first administration, and then every 2 h until hour 20, every 4 h from hour 20 to hour 40, every 2 h from hour 40 to hour 72, and then at 12-h intervals from hour 72 to hour 96. CMRT was calculated as described by Ehle et al. (1982). All six pigs in each treatment group were used to determine nutrient digestibility at the end of the trial. ...
... Additionally, variable factors that lengthen or shorten the intestinal passage time must be considered. These include, but are not limited to: the amount of ingested food and water, the feed composition (Ehle et al., 1982), the animal's breed, physiological state and body weight (Miraglia et al., 1992) as well as illnesses (e.g. diarrhea) (Istrate et al., 2014). ...
Artificial insemination (AI) is the most important biotechnology in pig reproduction. To achieve the best possible fertility results, appropriate timing of the insemination is essential. The optimal time for AI is 12 h before to 4 h after ovulation. This time-frame, unlike in estrus, is not recognizable through external indicators. It would, therefore, be beneficial to find simple and economical methods that support manual estrus checks and are able to determine the time of ovulation more accurately. On this basis, starting 80 h after weaning, 14 DanBred sows (parity: 5.2 ± 2.4) were checked for ovulation via ultrasound scans every 8 h over a period of 72 h. Additionally, rectal fecal samples were taken and analyzed for their estrogen concentration to assess possible relations to ovulation time. On average, sows ovulated 121 ± 10 h after weaning and 16 ± 9 h after onset of heat. There was a prominent drop in fecal estrogen levels 4 h before ovulation when compared to almost all other points in time (before ovulation: 20 h (P=0.056), 12 h (P=0.006); after ovulation: 4 h and 12 h (P<0.001)). There are, however, significant differences in the sow-individual fecal estrogen concentrations for which several influencing factors must be considered.
... In general, reducing particle size has been reported to improve feed efficiency and nutrient digestibility of weaned pigs (Kim et al., 2005;Mavromichalis et al., 2000). In addition, reduced particle size has also been found to increase cell wall degradation in pigs and rats fed diets based on wheat bran (Ehle et al., 1982;Nyman and Asp, 1985). Moreover, it appears that nutrient digestibility improves with increasing age of the pig, because of enhanced development of the digestive and absorptive capacity in the small intestine and increased colonization of carbohydrate-degrading micro-organisms in the large intestine (Fernandez et al., 1986). ...
The aim of the study was to evaluate the effects of fibre source (cassava residue, CR and sweet potato vines, SPV), particle size (1 mm and 3 mm screen size) and multi-enzyme supplementation (mixture of ␣-amylase, -glucanase, cellulase and protease) on growth performance and the coefficient of total tract apparent digestibility (CTTAD) in weaning and growing pigs (Landrace × Yorkshire). The experimental diets were based on maize, fish meal, full fat soybean, soybean meal, soybean oil and CR or SPV. The dietary levels of CR and SPV were 200 and 350 g/kg (as fed) in the post-weaning and growing period, respectively. The experiment was arranged according to a 2 × 2 × 2 factorial completely randomized design with five replications, and lasted 60 days with two periods: from 30 to 60 days of age (post-weaning) and 60 to 90 days of age (growing). In each period, pigs fed the CR diet had higher CTTAD of dietary components (except for ether extract), average daily gain and lower feed conversion ratio than those fed the SPV diet (P<0.05). The reduction in particle size increased the CTTAD of dietary components and average daily gain in the post-weaning period (P<0.05), but not in the growing period (P>0.05). Addition of the enzyme mixture improved the CTTAD and growth performance in the post-weaning period (P<0.05). There was an interaction between particle size and multi-enzyme supplementation on the CTTAD of crude protein and neutral detergent fibre (P<0.05) in the post-weaning period, such that multi-enzyme supplementation increased the CTTAD of CP and NDF in the larger particle size diet (0.80 versus 0.75, and 0.58 versus 0.51, respectively), while there was no changes in the small particle size diet (0.80 versus 0.78, and 0.59 versus 0.55, respectively). However, in the growing period multi-enzyme supplementation had no positive effect on the performance and the CTTAD of dietary components, with the exception of the CTTAD of crude protein and neutral detergent fibre. In conclusion, a reduction in particle size and multi-enzyme supplementation improved the CTTAD of dietary components and the growth performance in the post-weaning period, but not in the growing period.
... The gas production from fermentation of the substrates in the batch-culture system was analyzed after 36 and 48 h of incubation and for the entire progression within 48 h. The specifically selected incubation times indicate typical solid-phase mean retention times associated with fibers or feeds or diets rich in fiber within the large intestine or total digestive tract of pigs [2,27]. Gas production was in absolute terms lower than measured previously using wheat bran (63 vs. 124-180 mL/g DM) or sugar beet pulp (98 vs. 211-280 mL/g DM) as example [28][29][30][31]. ...
Dietary fibers may have positive impact on health and wellbeing of pigs. The study examined physicochemical properties of two lignocelluloses (including and excluding bark), powdered cellulose, Aspergillus niger mycelium, lucerne chaff, soybean shells, wheat bran, and sugar beet pulp in relation to fermentability and digestibility using in vitro batch-culture incubation. Maize starch and a purified cellulose were used as standardized substrates for classification of the test substrates. The substrates covered a wide range regarding their physicochemical properties. Swelling capacity (SC) was 9–411%, water binding capacity (WBC) was 4.4–14.3 g/g dry matter (DM), and water holding capacity (WHC) was 4.1–10.6 g/g DM. Gas production and other fermentation parameters—namely post-incubation pH, CH4, NH3, and short chain fatty acids (SCFA) concentrations—revealed a significant fermentation of sugar beet pulp, soybean shells, lucerne chaff, wheat bran, A. niger mycelium, and powdered cellulose, whereas the lignocelluloses were not fermented. Significant correlations were found between the physicochemical properties and the fermentation parameters (p < 0.05). Enzymatic pre-digestion mostly reduced gas, NH3, and SCFA production. In vitro digestibility of DM (IVDMD) and organic matter (IVOMD) was mostly negligible after enzymatic pre-digestion. Fermentation alone led to only 0.10–0.15 IVDMD and 0.14–0.15 IVOMD in lignocelluloses and powdered cellulose, respectively, but 0.44–0.37 IVDMD and 0.46–0.38 IVOMD in the remainder of substrates (p < 0.05). In vitro digestibility was again correlated with the physicochemical properties of the substrates and the fermentation parameters (p < 0.05). The fiber preparations and fiber-rich byproducts were fermented to a relevant extent. In contrast, lignocelluloses were not fermented and can be used rather as bulk material.
... The reason why PMS addition decreases nutrient digestibility may be due to the crude fibre in diets which accelerates the nutrients passing through the digestive tract. Table 1; a,b,c -means with different superscripts in the same column are significantly different at P < 0.05; FPA -filter paper activity of cellulase, CMC -carboxymethyl-cellulose activity of cellulase As it was previously reported, high dietary fibre level would prevent the contact of enzyme with feed to reduce the digestion of nutrients (Ehle et al., 1982;Le Gall et al., 2009). Also, dietary fibre was able to affect digestion and absorption of minerals such as Ca, P, Cu, Fe (Noblet and Le Goff, 2001;De Leeuw et al., 2008). ...
... In another study, the size of wheat bran particles had no effect on the fermentability of fiber in rats (Nyman and Asp, 1985). Similarly, there was no significant difference in the production of volatile fatty acids from coarse and fine wheat bran in the large intestine of pigs (Ehle et al., 1982). ...
... The higher cell wall digestibility for the coarse diet than that for the fine diet could be related to rate of passage. In growing-finishing pigs, the cell wall particles of the coarse diet had a significantly longer retention time (Fioramonti and Bueno 1980;Ehle et al. 1982). Therefore, larger particle size, with a longer retention in the pig than smaller particle size, would be expected to show a greater extent of cell wall digestion. ...
The effects of corn particle size on nutrient digestibility and energy utilization in pigs were determined under optimal (experiment 1, 25 ± 1 °C) or heat stress (experiment 2, 37 ± 1 °C) conditions. In Exp. 1 and 2, five experimental diets were tested using a 5 × 5 Latin square design involving five barrows (Landrace × Yorkshire × Duroc, average initial body weight of 30 ± 1 kg and 45.0 ± 1.8 kg, respectively, in individual metabolic cages). Dietary treatments were as follows: 200-, 300-, 400-, 600-, 800-μm corn particle sizes obtained by mesh screens. Under optimal thermal conditions, digestibility of dry matter (DM) and crude fiber (CF) from 200-μm diet was higher (P < 0.05) compared to that from the 300-μm and 400-μm diets. The digestibility of crude protein (CP) and ether extract (EE) was the highest (P < 0.05) at the 200-μm particle size. The apparent total tract digestibility of energy was significantly higher (P < 0.05) on the 200-μm diet. Under heat stress, digestibility of CF when corn was ground to 600 μm was higher (P < 0.05) compared to 300 and 400 μm. Digestibility of NDF and ADF was the highest (P < 0.05) at 600-μm corn particle size. In conclusion, grinding corn to 200-μm corn particles had a positive effect on DM, CP, EE, and CF under optimal thermal condition, while the 600-μm corn particle size had positive effects on digestibility of CF, NDF, and ADF than 200-μm corn particle size under heat stress.
... No differences were observed in SID values from the ileal samples collected in 4-, 6-, 8-, or 10-h periods compared with collection over the entire 12-h period, regardless of the time sample collection started, which indicates that 4 to 6 h of ileal sample collection starting any time during the day provides representative samples of ileal digesta from pigs fed a DDGS-based diet. Table 4. Standardized ileal digestibility (%) of dispensable AA and CP calculated based on collection of ileal digesta during different time periods from pigs fed a soybean meal-based diet 1,2 , as-fed basis The reason for the differences that were observed among diets for collection times are likely due to the high concentration of fiber in DDGS compared with corn and SBM (NRC, 2012), because increased fiber concentration in the diet may increase rate of passage and reduce transit time (Ehle et al., 1982;Kuan et al., 1983) and, therefore, increase the flow of DM to the distal ileum of pigs (Kim et al., 2016). Therefore, it appears that a more constant flow of AA reaches the distal ileum in pigs fed high-fiber diets compared with pigs fed diets containing less fiber. ...
The objective of this experiment was to determine the minimum collection time needed to obtain representative samples of ileal digesta from pigs fed different types of diets. Eight barrows with an initial BW of 34.6 kg (SD 2.1) were individually fitted with a T-cannula in the distal ileum and randomly allotted to a replicated 4 × 4 Latin square design with 4 diets and 4 periods per square. Three diets contained corn, soybean meal (SBM), or distiller’s dried grains with solubles (DDGS) as the sole source of CP. An N-free diet was also prepared. All diets contained 0.5% chromic oxide as an indigestible marker. Equal meals were provided at 0800 and 2000 h. Ileal digesta samples were collected in 2-h intervals from 0800 to 2000 h during the last 3 d of each 7-d period. When pigs were fed the corn diet, the standardized ileal digestibility (SID) of most indispensable AA and dispensable AA increased and then decreased (quadratic, P < 0.05) during each of the six 2-h periods. The SID of most AA were less (P < 0.05) if the ileal digesta samples were collected from 1800 to 2000 h or from 1600 to 2000 h compared with the SID values from the ileal samples collected over the entire 12-h period. When pigs were fed the SBM diet, the SID of Ile, Leu, Thr, Trp, Val, Ala, and Cys increased and then decreased (quadratic, P < 0.05) but the SID of all other AA linearly decreased (P < 0.05) during the six 2-h periods. The SID of almost all AA were greater (P < 0.05) if the ileal samples were collected from 0800 to 1000 h, from 0800 to 1200 h, from 1000 to 1400 h, or from 0800 to 1400 h but less (P < 0.05) if collected from 1600 to 1800 h, from 1800 to 2000 h, from 1600 to 2000 h, or from 1400 to 2000 h compared with the SID values from the ileal samples collected over the entire 12-h period. When pigs were fed the DDGSbased diet, the SID of Ile, Leu, Lys, Phe, Trp, Val, and Tyr increased and then decreased (quadratic, P < 0.05) during the six 2-h periods. The SID of most AA were less (P < 0.05) if the ileal samples were collected from 1800 to 2000 h compared with the SID values from the ileal samples collected over the entire 12-h period. In conclusion, diurnal variations in SID of AA in pigs indicate that 6 h of ileal sample collection starting 4 or 6 h after feeding may provide representative samples of ileal digesta from pigs fed different types of diets. © 2017 American Society of Animal Science. All rights reserved.
... Similarly, other studies have not observed a change in ileal or post-ileal VFA concentration in response to the addition of exogenous fiber degrading enzymes (Carneiro et al., 2008;Diebold et al., 2004;Yin et al., 2000). After being produced, VFA are absorbed rapidly (Bergman, 1990;Ehle et al., 1982), and only 10% of VFA is excreted in feces (Wolin and Miller., 1983). Thus, measurement fecal VFA concentration may not provide an accurate assessment of the impact the increase in dietary fiber and the addition of enzymes is having on the extent of fermentation. ...
A total of 135 pigs (initial weight = 7.2 ± 0.2 kg) were used to evaluate the effect of xylanase (XYL) and β-glucanase (BGL) alone or in combination (XB) on growth performance and nutrient digestibility in nursery pigs fed diets with corn/SBM and 30% corn distillers dried grains with solubles (CDDGS). Pens (n=30, 4–5 pigs per pen) were randomly assigned to one of five treatments: positive control (PC, Corn/SBM + 0% CDDGS), negative control (NC, 30% CDDGS replacing a portion of the corn and SBM with no enzyme addition), negative control + 4000 unit/kg xylanase (XYL), negative control + 450 unit/kg β-glucanase (BGL), and negative control + 4000 unit/kg xylanase + 450 unit/kg β-glucanase (XB). All pigs were fed a common phase 1 diet for one week post-weaning, and were switched to experimental diets in phase 2 (d7-21) and phase 3 (d21-35). Pigs fed the NC diet had reduced growth rate (P < 0.001) compared to PC. Pigs fed BGL diet had increased ADG by 7.7%, and those fed the XB diet had increased ADG (9.3%) over NC diet during d21-35 (P < 0.001). Overall, XB diet improved ADG by 6.6%, compared to NC diet (P < 0.001). Digestibility of DM, improved by 1.6 and 1.4% in pigs fed XYL and XB (P < 0.001), respectively. Overall, energy digestibility improved by 5.5% in pigs fed diets supplemented with enzymes (P < 0.001). Similarly, CP digestibility was 5.9% greater in pigs fed diets supplemented with enzymes as compared to the NC (P < 0.001). Addition of XYL, BGL, and XB increased average NDF, ADF, and hemicellulose digestibility by 33%, 30%, and 34%, respectively, when compared to NC diet (P <0.02). Supplementation of XYL, BGL, or both enzymes improved P digestibility (46%) when compared to NC diet (P < 0.01). The results indicate that ADG was improved by the XB combination, with most of the response accounted for by BGL. There was no effect of enzyme on ADFI or G:F. In contrast, XYL, BGL and XB improved nutrient digestibility. Enzyme supplementation at least partially reduced the negative impact of CDDGS on nutrient digestibility and growth.
... In another study, the size of wheat bran particles had no effect on the fermentability of fiber in rats (Nyman and Asp, 1985). Similarly, there was no significant difference in the production of volatile fatty acids from coarse and fine wheat bran in the large intestine of pigs (Ehle et al., 1982). ...
Increasing fiber consumption can address, and even reverse the progression of pre-diabetes and other associated non-communicable diseases. Understanding the link between plant dietary fiber and gut health is a small step in reducing the heavy economic burden of metabolic disease risks for public health. This book provides an overview of the occurence, significance and factors affecting dietary fiber in plant foods in order to critically evaluate them with particular emphasis on evidence for their beneficial health effects.
... Relation entre le temps moyen de transit et la teneur en NDF de la ration.Canguilhem and Labie (1977);Castle and Castle (1956);Castle and Castle (1957);Cherbut et al. (1988);Ehle et al. (1982);Fioramonti and Bueno (1980);Furuya and Takahashi (1975);Furuya et al. (1978);Kuan et al. (1983);Pond et al. (1986);Potkins et al. (1991);Roth and Kirchgessner (1985);Sandoval et al. (1987);Stanogias and Pearce (1985) of endogenous flow of constituent i in AC c fractional rate of flow of DM from AC b to AC c fractional rate of faecal flow of DM c fractional rate of uptake of constitue nt i for microbial growth in LIC uptake of constituent i for microbial growth in LIC maximum v elocity for absorption flow of constituent i in AC c efficiency of microbial growth with respect to g Qi,e + KAi,e ) dQi,LIC/ dt = Fi,SI2 . LIC + 0 ji,LIC + Ei,LIC-(Fi,FEc+ 0 ij,LIC+Ai,LIC+Ui,LIC) dQMic/ dt = GMIC -FMIC, . ...
The applications for mechanistic modelling in the field of animal sciences are numerous, and are as important for practical purposes as for research and teaching. One of its most important possibilities is the prediction of the laws of response of the animal to its environment. This approach allows growth, quality of products, excretion, etc. to be taken into account simultaneously even in non-standard conditions. In the pig, most of the models published to date concern the growth of animals. These models include the main determining factors for the partition of nutrients between the functions of maintenance and growth, but the digestive step is generally not described. Besides, the time step considered is most often one day, which does not allow satisfactory modelling of metabolism since the dynamics of nutrient supply can be of importance. Some models describe in part aspects of digestion (gastric emptying, transit, degradations) but no one covers this function as a whole. A simple model of digestion in the pig was developed from data available in literature. lt includes four anatomical compartments (stomach, two portions of small intestine, large intestine) between which the transit of digesta is represented. ln these anatomical compartments, the main digestive events (degradation, absorption, endogenous secretion) are described for the various fractions of digesta (proteins, starch, triglycerides, dietary fibre, minerals). In addition, microbial fermentation is taken into account in the large intestine. The total number of compartments is 44. The time step used is 1 minute. Thus, the model allows the simulation of the evolution of the level and composition of each anatomical compartment with time, as well as the kinetics of absorption of nutrients. The comparison of the outputs of the model with data from literature shows that the general behavior of the model is sound. Its structure can be used as a basis for further developments and could take into account additional variation factors of digestive processes. An application of this model is the study of endogenous nitrogen secretion. Data from the literature on endogenous nitrogen flow at the ileum are quite variable and sometimes contradictory. This parameter is though essential for the interpretation of ileal amino acid digestibility results. A quantitative study performed on about one hundred published results shows that some major variation factors such as feeding level or fibre content of feed can be identified and quantified when the effects of experimental procedures are taken into account. The amino acid profile of endogenous protein flow at the ileum is less variable and an estimation of the non specific part of endogenous secretions is proposed. A complementary approach was to list the various sources of endogenous nitrogen supply in the gut, and to adapt the model of digestion to represent the transit, the degradation and the absorption. The results are in agreement with the trends of the quantitative literature review. Moreover, the simulation allows an estimation of some factors which are difficult to measure in experiments: kinetics of absorption of endogenous amino acids, follow up through time of the quantities of proteins of endogenous origin at the different levels of intestine. Some perspectives for development and improvement of this type of model are then discussed : how to maintain a simple representation of transit that accounts as precisely as possible for the kinetics of digestive events, and particularly of the minimum time of transit through the small intestine; to what extent can a model of digestion be of use in the prediction of feed digestibility, what are the perspectives for the use of such an approach in growth models and metabolism models, and in excretion modelling.
... Em relação à digestibilidade da fração FDN, foi detectado decréscimo linear com o aumento da fibra na dieta (Tabela 3), concordando com os resultados obtidos porKass, Van Soest e Pond (1980) eEhle et al. (1982). Para cada unidade percentual de FDN adicionada à ração basal, houve redução de 0,95%na digestibilidade desta fração. ...
Fêmeas suínas destinadas à reprodução devem seguir um plano de restrição alimentar objetivando controlar excessiva ingestão calórica. Emprego de alimentos volumosos, devido ao seu alto teor de fibra, fornece menor aporte de energia para suínos. Esta estratégia alimentar contorna o problema da acumulação excessiva de gordura corporal. Objetivando estudar estes aspectos, fêmeas pré-púberes e púberes foram alimentadas com rações isoenergéticas e isoprotéicas contendo 0; 6,6; 13,2 e 19,8% de fibra em detergente neutro (FDN), obtidas pela inclusão de feno de coast-cross. Vinte marrãs mestiças foram empregadas em um delineamento experimental de blocos casualizados, que durou 97 dias. Após, os animais foram sacrificados. O incremento de FDN na ração diminuiu o ganho de peso linearmente (0,675; 0,607; 0,525; 0,483 g/dia); o peso corporal ao primeiro cio útil (118,0; 114,0; 102,2; 98,2 kg) e piorou a conversão alimentar (3,6; 4,0; 4,7; 5,3). Observou-se resposta quadrática na espessura de toucinho (3,28; 3,34; 2,82; 1,74 cm). Não houve efeito sobre a idade de ocorrência do primeiro cio útil (203 dias) e no rendimento de carcaça quente; entretanto, foram obtidas respostas quadráticas para o rendimento de carcaça fria (79,79; 80,24; 79,58; 77,40%) e de carne magra (54,45; 54,35; 55,51; 58,31%). Níveis crescentes de FDN reduziram linearmente os coeficientes de digestibilidade da matéria seca (76,23; 67,23; 55,83; 55,73%) e da fibra em detergente neutro (56,63; 44,24; 34,17; 39,12%); houve respostas quadráticas para a proteína bruta (72,16; 64,46; 53,52; 62,74 %) e energia bruta (71,95; 61,23; 49,21; 53,81%). A condição corporal necessária para fêmeas reprodutoras não foi prejudicada pelo oferecimento de ração fibrosa durante as fases de pré-puberdade e puberdade.
... Pigs are non-specialist feeders and are able to digest fibre (Cunningham et al. 1962;Wenk 2001) although their energy intake from fibre should not be overestimated (Ehle et al. 1982;Dierick et al. 1989). However, feral pigs and wild boar normally rely heavily on highly energetic and patchily distributed food, such as fruit and insects, in their omnivorous diet (Stolba and Wood-Gush 1989;Umberto 2007), making them rather selective foragers. ...
Recently, foraging strategies have been linked to the ability to use indirect visual information. More selective feeders should express a higher aversion against losses compared to non-selective feeders and should therefore be more prone to avoid empty food locations. To extend these findings, in this study, we present a series of studies investigating the use of direct and indirect visual and auditory information by an omnivorous but selective feeder—the domestic pig. Subjects had to choose between two buckets, with only one containing a reward. Before making a choice, the subjects in Experiment 1 (N = 8) received full information regarding both the baited and non-baited location, either in a visual or auditory domain. In this experiment, the subjects were able to use visual but not auditory cues to infer the location of the reward spontaneously. Additionally, four individuals learned to use auditory cues after a period of training. In Experiment 2 (N = 8), the pigs were given different amounts of visual information about the content of the buckets—lifting either both of the buckets (full information), the baited bucket (direct information), the empty bucket (indirect information) or no bucket at all (no information). The subjects as a group were able to use direct and indirect visual cues. However, over the course of the experiment, the performance dropped to chance level when indirect information was provided. A final experiment (N = 3) provided preliminary results for pigs’ use of indirect auditory information to infer the location of a reward. We conclude that pigs at a very young age are able to make decisions based on indirect information in the visual domain, whereas their performance in the use of indirect auditory information warrants further investigation.
... Ressalte-se também o efeito inibitório da lignina sobre a digestibilidade dos constituintes da parede celular DEHORITY, 2000). Para os herbívoros não-ruminantes, a utilização da celulose pelos microrganismos intestinais é altamente prejudicada pelo menor tempo de permanência da digesta no intestino grosso (EHLE et al., 1982). Em conseqüência, geralmente observa-se relação inversa entre a fração de fibra presente na dieta e a digestibilidade da matéria seca (KING; TAVERNER, 1975). ...
Objetivando avaliar os efeitos de ração fibrosa sobre parâmetros de digestibilidade dos nutrientes, de desempenho produtivo e de características de carcaça, realizou-se o presente experimento, utilizando 24 suínos mestiços, durante as fases de crescimento e terminação, em delineamento blocos inteiramente casualizados. Os animais foram alimentados à vontade com rações isonutrientes contendo incrementos de 0 ou 8% de fibra em detergente neutro (FDN), obtidas através da inclusão de 0 ou 10% de feno de “coast-cross” (Cynodon dactylon). Na fase de crescimento, os tratamentos diferiram para a digestibilidade da matéria seca, energia bruta, proteína bruta e fibra em detergente ácido com piora nos valores para a ração com 8% de FDN. Na fase de terminação, houve diferença na digestibilidade para matéria seca, energia bruta, proteína bruta, fibra em detergente neutro e fibra em detergente ácido com redução nos índices para a ração com 8% de FDN. A inclusão de 8% de FDN não alterou o peso corporal final, ganho de peso, conversão alimentar, rendimentos de carcaças quente e fria, rendimento de carne magra e área de olho de lombo. Os resultados indicaram que o contínuo oferecimento de relativamente baixo teor de FDN alterou a digestibilidade dos componentes dietéticos da ração. Entretanto, como os parâmetros referentes ao desempenho animal e às características de carcaça não foram comprometidos, vislumbrase real possibilidade de emprego de moderadas quantidades de materiais fibrosos na alimentação de suínos, nas fases de crescimento e terminação.
... Fevrier et al. (1992) reported that an increase in NDF is the most important factor that reduces nutrient digestibility. As NDF increases in the diet, however, more potentially energy-yielding nutrients are transported to the hindgut where a part of the carbohydrates are fermented to volatile fatty acids (Ehle et al., 1982). The fermentation process, however, has a much lower metabolic efficiency compared with when glucose is absorbed directly from the small intestines (Whittemore, 1993). ...
A study was conducted to compare the digestibility of organic matter (OM), neutral-detergent fibre (NDF), acid-detergent fibre (ADF), hemicellulose and nitrogen (N) and N balance in Mukota (M), Large White (LW) and the LW × M F 1 pigs. Four male pigs of each breed, at proportionately 0·3 of their mature body weights, were randomly allocated to each of four diets in a cross-over design. The diets, which were formulated to contain similar levels of protein (ca . 160 g crude protein per kg) and energy (ca . 9 MJ metabolizable energy per kg), contained 0, 100, 200 and 300 g maize cob meal per kg, which corresponded to NDF levels of 276·4, 360·3, 402·9 and 523·5 g/kg dry matter, respectively. There was a negative correlation (P < 0·001) between the digestibility of OM, NDF, ADF and hemicellulose and the level of NDF in the diet. The digestibility of OM, NDF, ADF and hemicellulose decreased linearly (P < 0·05) with increase in the level of NDF among all three genotypes. There was a genotype × diet interaction on NDF and ADF digestibilities with digestibility in the LW decreasing faster (P < 0·05) than in the Mukota and LW × M F 1 cross with increasing NDF. Both breed and level of maize cob meal affected N digestibility (P < 0·001), whilst the N retained per unit metabolic body weight was only affected by diet (P < 0·01). Increasing the level of maize cob meal beyond 100 g/kg, however, did not reduce N digestibility (P < 0·05). There was neither genotype nor dietary effect (P > 0·05) on N retained per unit N intake. These findings showed that the Mukota and the LW × M F 1 cross were better able to digest the fibrous components than the LW. In addition, the Mukota and the LW × M F 1 cross displayed an ability to retain protein to the same extent as the LW.
... A number of studies have determined that diet can affect fermentation acid concentrations of the GI tract (Ehle et al., 1982;Andrieux et al., 1989;Tortuero et al., 1994), with fiber and/or indigestible carbohydrates being the most effective in promoting increases of these fermentation byproducts. It remains problematic however, that significant fiber inclusion, which dilutes important nutrients in grower diets, negatively affects gain and feed efficiency in swine. ...
... In this experiment, the fermented agro by-products diet was substituted by 100% of formula feed. Moreover, supplemental high fiber diet was found to decrease ADG and feed efficiency (Ndindana et al., 2002) as well as reduced ileal digestibility of nutrients (Ehle et al., 1982). Therefore, the ADG might be affected by digestibility of nutrients or diet ingredients. ...
Effects of a supplemental fermented agro by-products diet on growth performance, blood characteristics and carcass traits were investigated in fattening pigs. The fermented diet mainly contained 38.0% brewer's grain, 25.0% rice bran and 21.0% byproduct of king oyster mushrooms. The mixed ingredients were fermented at for 7 days and fed to crossbred barrow pigs for 62 days. Ninety pigs were housed in 10 head per pen with three replicate pens per treatment. The pigs in the control group were fed with formula feed, while the pigs in T1 group were fed 20, 40, 60, 80 and 100% fermented diet substituted with formula feed on 1 week interval. Pigs in T2 group were fed 30, 60 and 100% fermented diet substituted with formula feed on 1 week interval. The fermented diet significantly (p
... In vitro methods for ruminants based on rumen fluids have been in use for some time (Tilley and Terry 1963). The use of rumen fluid has also been made in developing methods with application to the pig (Vervaeke et al. 1979) while other workers have used pig intestinal fluids directly (Furuya et al. 1979;Ehle et al. 1982). Löwgren et al. (1989) described an in vitro system with 3 different inocula from duodenal fluid, ileal fluid, and faeces extract. ...
The philosophy inherent in developing in vitro digestibility assays for dietary energy and protein is reviewed and an historical account is given of the development of such assays for the pig. General principles to be considered in the development of in vitro digestibility assays are discussed, as are limitations of the in vitro approach. The importance of choosing the most appropriate in vivo measures of digestibility for the evaluation of in vitro assays is stressed. For protein sources that do not contain anti-nutritional factors or plant fibre, ‘true’ ileal digestibility should be the in vivo baseline, while plant proteins should be tested against ‘real’ ileal digestibility. There is a dearth of adequately conducted validation studies for in vitro digestibility assays. It appears that the 3-step (pepsin, pancreatin, Viscozyme) closed in vitro system to allow prediction of organic matter and gross energy digestibility in the pig has particular promise for practical feed evaluation. Similarly based protein digestibility assays may require further development before they can be applied with confidence.
... The current data are supported by Kuan et al. (1983) and Stanogias and Pearce (1985) who reported a similar response to increasing dietary fiber, where apparent total tract digestibility of CP, DM, and EE decreased due to increasing fiber. Also, fiber type has been reported to decrease digestibility of the cell wall, NDF, DM, CP (Ehle et al., 1982), AA , and TDF . Plasma urea N and triglycerides increased (P < 0.01) as dietary fiber increased, ...
Experimentation in research explores new ideas and helps gain new knowledge which includes treatment observations, laboratory analyses, statistical analyses, and interpretation of the data. The use of appropriate methodology plays an important role in high quality research as it helps yield accurate, reliable and repeatable data. The same components can be analyzed by multiple methods due to the accumulation of approved methods. In this thesis two methodologies have evaluated to make suggestions based on time, budget, and resource availability. Currently there are several accepted methods for the drying of animal excreta; however some methods have been reported to negatively impact the nutrient composition more than other methods. Therefore, one objective of this thesis was to evaluate nutrient and energy losses due to drying method on feces, urine, and poultry excreta. Twelve individually penned growing pigs were fed one of three diets and 16 pens of 10 growing broilers were fed one of four diets that differed in nutrient composition. Feces, urine, and excreta that varied in nutrient composition were collected after 7 d of diet adaptation. Samples were dried using one of four methods: UD-undried, FD-freeze dried, OD55-oven dried at 55yC for 48 h, or OD100-oven dried at 100yC for 48 h, after which DM, GE, N, C, and S were determined. There were no differences among drying methods except FD excreta had a greater S concentration than OD (P < 0.10). Covariates are auxiliary variables used in the statistical covariance analysis to limit variation for accurately calculating the least squares means.
Digestibility research has shown limited use of covariates because the benefits are unknown. Therefore, the second objective of this thesis was to determine an appropriate covariate for digestibility experiments to limit variation that may affect treatment observations. Seventy two barrows were randomly assigned to one of three dietary treatments for Phase-1 (P1; 14 d). On d-14, pigs were randomly reassigned to one of the three diets within initial dietary treatment for Phase-2 (P2; 14 d). Fecal and blood samples were collected on d-10 or d-14 of P1 and d-14 P2. Fecal samples were dried and analyzed for C, ether extract, GE, N, NDF, P, and S. Plasma samples were analyzed for plasma urea nitrogen and triglycerides. When P1 criterion was used as a covariate for P2 data, it was significant for C, ether extract, GE, NDF, N, S, and plasma urea nitrogen (P < 0.10). In conclusion, the data indicate that if initial diets are known, one must balance subsequent treatments for the initial diet because of potential diet by diet interactions. If the initial diets are not known, then an initial criterion would be effective in reducing the variation associated with subsequently obtain data, and should be considered as a covariate in future nutrition research. Therefore, the methods utilized and processed are important for yielding accurate and precise data.
... In growing pigs, fibre sources with lignified cell walls are more resistant to microbial activity, and more effective in increasing the faecal volume and reducing digesta transit time (Latymer et al., 1985). The capacity of the pig to digest and utilise fibre is affected by the source of the fibre (Ehle et al., 1982b) and lignin content (Mitaru et al., 1984). Stanogias and Pearce (1985) showed that the extent of fibre digestibility depends predominantly on the origin of the fibre and to a lesser extent on the amount of fibre in the diet. ...
The digestibility of high-fibre diets and digesta passage was measured in growing pigs and attempts were made to predict the in vivo digestibility from in vitro data. In Experiment 1, six diets were formulated to measure digestibility using low-fibre cassava starch, fish meal and soya bean meal in combination with six locally available fibre sources. Four green plants: banana sheaths (Musa paradisiaca), duckweed (Lemna minor), sweet potato vines (Ipomoea batatas) and water spinach (Ipomoea aquatica) were used for the BS, DW, SPV and WS diets, respectively. In addition two by-products, copra meal (CM) and tofu residues (TR), were used for the CM and TR diets, respectively. Digesta retention of solids was measured using chromium mordanted Para grass (Brachiaria mutica) fibre and Co–EDTA was used for the retention of liquid.
... The relation between digestion of hemicellulose and cellulose of alfalfa-and grass-based diets and body weight for diverse species of ruminants and nonruminants [Van Soest, 1994]. Data of Dierenfeld et al. [1982], Ehle et al. [1982], Foose [1982], Keys et al. [1969], Keys and Van Soest [1970], Milton and Deminent [1988], Uden and Van Soest [1982a], and Van Soest et al. [1978]. Identification of species: antelope, A; grazing bovids, B; camelids, C; deer, D; elephants, E; giraffe, G; humans, H (shown in the figure by the vertical lines); baboons, M; hippo, 0; rhino, P; horses, Q; rodents and lagomorphs, R; sheep and goats, S; tapirs, T; pigs, U; panda, X; zebras, Z. 1982a]. ...
The purpose of this review is to give some perspective of the factors that influence feeding behaviors and the ability of herbivores to adapt to diets. The most important of these are digestibility, ability to select feed, and achievement of a nutritionally adequate intake. Plant morphology, observed feeding behavior, body size, and gut architecture and size impinge upon these factors. Feeding behavior and dietary specializations are associated with adaptations of gut and mouth parts as well as body size. Parallel and overlapping behaviors occur among herbivores and particularly between ruminants and nonruminants. The conventional classifications of grazers, browsers, and selective feeders are blurred by these evolutionary developments. © 1996 Wiley-Liss, Inc.
... The current data are supported by Kuan et al. (1983) and Stanogias and Pearce (1985) who reported a similar response to increasing dietary fi ber, in which apparent total tract digestibility of CP, DM, and EE decreased because of increasing fi ber. Also, increased dietary fi ber type has been reported to decrease the digestibility of NDF, DM, and CP (Ehle et al., 1982), AA (Pedersen et al., 2007), and total dietary fi ber . Plasma urea N and triacylglycerides increased (P < 0.01) as dietary fi ber increased, but delineating the response is confounded due to the increase in dietary CP and crude fat. ...
Covariance analysis limits error, the degree of nuisance variation, and overparameterizing factors to accurately measure treatment effects. Data dealing with growth, carcass composition, and genetics often utilize covariates in data analysis. In contrast, nutritional studies typically do not. The objectives of this study were to: 1) determine the effect of feeding diets containing dehulled degermed corn, corn-soybean meal, or distillers dried grains with solubles on nutrient digestibility coefficients, 2) evaluate potential interactive effects between initial and final treatment diets on the final treatment diet effects, and 3) determine if initial criterion (digestibility or physiological values) would effectively correct for variation among pigs that could thereby affect final treatment diet digestibility coefficients. Seventy two crossbred barrows [(Yorkshire × Landrace × Duroc) × Chester White] were randomly assigned to 1 of the 3 diets within initial dietary treatment for Phase-2 (P2; 14 d). Fecal and blood samples were collected on d 14 of P1 and d 14 of P2. Fecal samples were dried and analyzed for C, ether extract, GE, N, NDF, P, and S. Plasma samples were analyzed for plasma urea nitrogen and triacylglycerides. Pigs were fed diets differed widely in CP, NDF, and P, resulting in an overall decrease in C, GE, NDF, N, P, and S digestibility, and plasma urea nitrogen and triacylglycerides as dietary fiber increased in P1 and P2 (P < 0.10). There were no differences in P2 criteria due to blocking for the P1 diet. There tended (P = 0.10 to 0.20) to be P1 × P2 interactions for NDF and S, indicating that the response of pigs to the P2 diet may depend on the P1 diet. In contrast, when the P1 variable was used as a covariate for P2 data, it was statistically significant for GE, NDF, N, S, and plasma urea nitrogen (P < 0.10), while C and ether extract showed tendencies, but not for P digestibility or plasma triacylglycerides. In conclusion, if initial diets are known, subsequent treatments should be balanced for the initial diet because of potential of initial diet by final diet interactions. If the initial diets are not known, then the initial digestibility coefficient would be effective in reducing the variation associated with subsequently obtained data, and should be considered as a covariate in future grower-finisher swine digestibility research.
Pars oesophageal gastric ulceration is a prevalent condition in swine production and often observed in finisher pigs at slaughter, with reported prevalence ranging from 32% to 65%. Although feeding practices in nursery and finisher pigs are similar, little is known about the prevalence and risk factors associated with this condition in nursery pigs.
This prospective cohort study aimed to identify risk factors for gastric ulceration in nursery pigs. The objectives were: (1) to estimate the association of inherent pig characteristics (birth weight, sex, parity of sow, litter size, and pen fouling behavior) and management characteristics (antibiotic treatment during suckling and post weaning, piglet rotation during lactation, weaning age and weight) with pars oesophageal lesions; (2) to assess differences in gastric dry matter content, pH, and percentage of solid particles in the sediment in relation to pars oesophageal lesions.
A total of 58 piglets tracked from birth to 20 days of age and 210 nursery pigs from birth to 10 weeks of age were euthanized and assessed for pars oesophageal gastric lesions. All nursery pigs were fed finely ground pelleted feed ad libitum. Based on a macroscopic assessment, the pigs’ stomachs were categorized as either LPO “lesions in the Pars oesophagea” or NLPO “no lesions in the Pars oesophagea”.
We observed an overall prevalence of 26.2% (CI 95% 0.67 – 0.79) for LPO in nursery pigs at 10 weeks of age, while no lesion were observed in piglets at 20 days of age. A mixed multivariable logistic regression model showed that piglets with a birthweight ≤ 1.11 kg had a 2.11 times higher odds of LPO (CI 95% 1.02 – 4.37, p = 0.04) than their heavier counterparts. There was a weak association of LPO in nursery pigs from pens with pen fouling with a 2.14 times higher odds (CI 95% 0.97 – 4.72 p = 0.05). Nursery pigs with LPO presented an increased gastric content fluidity with a reduced (p ≤ 0.01) gastric dry matter content (18.7%), solid phase (74.7%), and pH (3.22) compared to NLPO nursery pigs (20.5%, 85.09%, 3.56, respectively).
We have demonstrated that LPO are present in nursery pigs as early as 10 weeks of age. We observed that low birth weight is associated with higher odds for LPO in nursery pigs. These observations might help explain differences between individual pigs in terms of LPO development when groups are exposed to similar environments, management, and feeding conditions.
Accurate knowledge of the actual nutritional value of individual feed ingredients and complete diets is critical for efficient and sustainable animal production. For this reason, feed evaluation has always been in the forefront of nutritional research. Feed evaluation for poultry involves several approaches that include chemical analysis, table values, prediction equations, near-infrared reflectance spectroscopy, in vivo data and in vitro digestion techniques. Among these, the use of animals (in vivo) is the most valuable to gain information on nutrient utilization and is more predictive of bird performance. However, in vivo methods are expensive, laborious and time-consuming. It is therefore important to establish in vitro methods that are reliable, rapid and practical to assess the nutritional quality of feed ingredients or complete diets. Accuracy of the technique is crucial, as poor prediction will have a negative impact on bird performance and, increase feed cost and environmental issues. In this review, the relevance and importance of feed evaluation in poultry nutrition will be highlighted and the various approaches to evaluate the feed value of feed ingredients or complete diets will be discussed. Trends in and practical limitations encountered in feed evaluation science, with emphasis on in vitro digestion techniques, will be discussed.
In pig production, production efficiency is effectuated by formulating diets that meet the pigs’ nutrient requirement for maintenance and production (i.e. growth, reproduction). The amount of nutrients available to the pig, depends on the nutrient content of the diet and on the ability of pigs to digest and absorb these nutrients from their gastrointestinal tract. The availability, but also the utilization of absorbed nutrients for metabolic processes (e.g. heat production, protein and fat synthesis), depends on the kinetics of nutrient digestion after ingestion of feed. Digestion is the aggregated process of passage, hydrolysis, and absorption of nutrients and endogenous secretions by organs and tissues involved. These processes determine at what rate and to what extent (i.e. kinetics) nutrients are digested and absorbed. Current feed evaluation systems, used to formulate pig diets, do not take into account the kinetics of nutrient digestion. To gain insight into the impact of nutrient digestion kinetics on absorption of nutrients in pigs, a computer model was developed as aim of the research described in this thesis.
The work described in this thesis provides insight on the quantitative relations between the kinetics of digesta passage and diet viscosity (Chapter 2), diet solubility, and feed intake level (Chapter 3). In addition, the thesis presents further data on the variation in protein hydrolysis kinetics among feed ingredients used in practice for pigs diets (Chapter 4). The dynamic mechanistic computer model: ‘SNAPIG’, described and evaluated in this thesis (Chapter 5), simulates variation in the kinetics of nutrient digestion and absorption in growing pigs. It is a promising tool that can be used to predict the kinetics of nutrient absorption in pigs fed diets varying in feed ingredient and physicochemical properties.
Short-chain fatty acids (SCFAs) are produced when undigested dietary constituents are fermented by anaerobic bacteria in the intestine (Bancroft et al., 1944). Dietary fiber has been suggested to be the main substrate for the production of SCFAs. The SCFAs are readily absorbed and play significant physiological roles in the host. For example, butyrate is proposed to be a preferable fuel to glucose, glutamate, or ketone bodies for colonocytes (Roediger, 1982), whereas acetate and propionate are mainly converted to fatty acids and glucose, respectively, in the liver (Demigne et al., 1986). In addition, SCFAs are involved in the maintenance of secretory and absorptive functions in the large intestine by affecting movement of water and electrolytes (Argenzio et al., 1975). Therefore, investigation of the production of SCFAs through the fermentation of dietary fiber and evaluation of the mechanisms involved in the absorption are of interest. In this chapter we focus on absorption of SCFAs with a brief overview of production.
Feeding pregnant sows with a bulky diet rich in dietary fibers could improve animal welfare without providing excessive feed energy. However, this type of diet would have an impact on manure volume and composition, and a diet treatment to improve sow welfare by reducing their persistent hunger cannot be recommended without examining its impact on manure composition and handling. This study investigated the effects of high-fiber diets on the daily production and physico-chemical characteristics of manure slurry from pregnant sows. Three isoenergetic diets, very high-fiber (VHF), high fiber (HF), and concentrated (C), were fed twice daily to two groups of four fourth parity pregnant sows. Fecal and urine production was measured separately on days 17 and 18 of the 21-day treatment period. Physico-chemical analyses were performed on a slurry sample (mixture of feces and urine). Dietary fiber addition significantly (P < 0.05) increased fecal mass but tended to decrease urine production. Consequently, manure slurry (feces plus urine) production was similar with all diets, but total solids (TS) content was significantly increased (P < 0.05) as fiber addition increased. Mean TS concentration was 3.8, 11.1, and 18.3% in the manure from sows fed the C, HF, and VHF diets, respectively. As a result, manure slurry consistency was changed from a liquid state (less than 10% TS) when the C diet was fed to a semi-solid state (TS content between 10 and 20%) with the two high fiber diets. The use of high fiber diets may thus cause a challenge with the liquid manure handling, storage, and land application systems currently used on many commercial farms. Other major changes in manure slurry characteristics due to dietary fiber incorporation included significant (P < 0.05) increases in apparent viscosity, total and soluble chemical oxygen demand, and volatile fatty acid concentrations. Total amount of mineral elements excreted in the manure slurry was not affected by dietary fiber addition.
Sixteen hybrid weaned pigs from imported improved breeds, with an average initial weight of 9.15 ± 0.12 kg, were used to evaluate feed intake (g/d), average daily gain (g), feed to gain ratio and carcass characteristics of pigs slaughtered at 49.9 ± 3.7 kg in Cameroon. The cost to produce one kg live weight gain of pigs was also determined. The piglets were randomly divided into 4 treatments and were fed ad libitum diets containing 2,600, 2,800, 3,000 and 3,200 kcal digestible energy (D.E.) /kg of feed during a 75-days experimental period. Results showed no significant effect of dietary energy (P>0.05) on daily feed intake and average daily gain. Feed to gain ratio was significantly lower in pigs receiving the diet containing 3,200 kcal D.E. digestible energy/kg (control diet) than in others (p<0.01). The cost of feed to produce 1 kg live weight gain was significantly lower in diet providing 2,600 kcal D.E./kg (p<0.01.) than in the one containing 2,800 kcal D.E./kg, which was also reduced as compared to the other feeds. Carcass analysis of pigs slaughtered showed that the pigs which ate the diets with 2,600 or 2,800 kcal D.E./kg (p<0,05) were the leanest. It can be concluded that the use of the low digestible energy diet, with 2,600 kcal D.E./kg, is the most economical and does not induce a drastic decline in growth performance. High fibre content local feeds resources may be of interest for feeding growing pigs in Cameroon.
THERE IS CURRENTLY STRONG INTEREST IN DEVELOPING A BETTER understanding of the probable food habits and dietary niche of early humans (Isaac 1978; Peters and O'Brian 1981; Stahl 1984). Without such information, we are handicapped in our ability to interpret the significance of many features of human morphology and to construct viable models of early human ecology (Isaac 1978; Sussman 1978). Further, it is increasingly obvious that many of the major health problems faced today by more modern technological societies stem from factors related to diet. This strongly suggests that the average diet in such societies is not entirely suitable for human nutritional needs (Burkitt, Walker, and Painter, 1972; Trowell 1978; Truswell 1977). In this paper, I review information about dietary choice in primates, paying particular attention to members of the Hominoidea. I then examine features of the human gut, comparing it with the guts of other mammals, both primates and non-primates, to distinguish any features that appear to set humans apart. I conclude by speculating on the probable diet of early humans, using the behavior of extant pongids as a partial foundation for my speculations.
The large intestine of the chicken differs both anatomically and physiologically from the pig's large intestine and the men of the cow. The chicken's large intestine is less developed than the pig's large intestine or the cow's lumen. This paper summaries these differences. The chicken's large intestine contains a microbiological population similar to that found in the rumen. The chicken's caeca especially contains a large number of microorganisms, but this population varies according to age, fred, maturity, antibiotic use and etc.. Protein is an essential nutrient for the formation of intestinal microvilli. A study showed that the length of the small intestine was 63 % of the total gastrointestinal tract (GIT) length, while caecum was 8.1 %, and the colon and rectum were 4.6 %. The establishment of the microbial population of the small intestine occurs earlier than that of the caeca, but the identity of approximately 90 % of microbial population of the chicken GIT is hon. Recent studies have shown that energy, volatile fatty acid (VFA) and electrolytes that are found in the large intestine may be absorbed to a certain degree. The chicken small intestine is the primary location for digestion with a variety of enzymes being secreted here. Much research is being conducted into the digestion of sucrose thermal oligosaccharide caramel (STOP), fructooligosaccharides (FOS), mannanoligosaccharide (MOS), galactooligosaccharides (GOS) and isomalto-oligosaccharides (IMO) in the chicken caeca and large intestine. Excessive fibre content in the feed has detrimental effects, but proper fibre supplementation to chicken diets can improve the length and capacity of the small intestine.
The human intestinal microbial ecosystem plays an important role in maintaining health. A multitude of diseases including diarrhoea, gastrointestinal inflammatory disorders, such as necrotising enterocolitis (NEC) of neonates, and obesity are linked to microbial composition and metabolic activity. Therefore, research on possible dietary strategies influencing microbial composition and activity, both preventive and curative, is being accomplished. Interest has focused on pre- and probiotics that stimulate the intestinal production of beneficial bacterial metabolites such as butyrate, and beneficially affect microbial composition. The suitability of an animal model to study dietary linked diseases is of much concern. The physiological similarity between humans and pigs in terms of digestive and associated metabolic processes places the pig in a superior position over other non-primate models. Furthermore, the pig is a human-sized omnivorous animal with comparable nutritional requirements, and shows similarities to the human intestinal microbial ecosystem. Also, the pig has been used as a model to assess microbiota-health interactions, since pigs exhibit similar syndromes to humans, such as NEC and partly weanling diarrhoea. In contrast, when using rodent models to study diet-microbiota-health interactions, differences between rodents and humans have to be considered. For example, studies with mice and human subjects assessing possible relationships between the composition and metabolic activity of the gut microbiota and the development of obesity have shown inconsistencies in results between studies. The present review displays the similarities and differences in intestinal microbial ecology between humans and pigs, scrutinising the pig as a potential animal model, with regard to possible health effects.
An attempt has been made to assess some quantitative aspects of the influence of fibre content in feedstuffs and diets on the digestibility and absorption of nutrients in pigs. The study is based on selected published literature and data from Danish experiments. The digestibility of nutrients consistently decreases with increasing fibre content in the diet, regardless of the analytical method used. However, the magnitude of this negative influence depends on the type and origin of the fibre source, technical treatment, feeding level, age and live weight of the pigs, etc. Increasing the content of crude fibre in diets is related to increasing the content of less digestible carbohydrate (hemicellulose) and a concurrent decrease in the content of easily digestible substances. It is shown that for each 1% increase in the crude fibre content, the content of starch + sugars in the NFE-fraction is decreased by 2.1-2.7%. This results in a reduced ileal digestibility, enhanced fermentation in the hindgut and an overall reduction of the digestibility of gross energy. Experimental data from this institute comprising 246 diets and 257 single feedstuffs were used to generate equations for prediction of the digestibility of gross energy. A single carbohydrate fraction (NDF or crude fibre) alone accounted for about 70% of the variation in digestibility in diets and 85% of the variation in digestibility of single feedstuffs. Fibre determination values based on either detergent methods (NDF) or crude fibre analysis supplemented with enzymic determination of starch + sugars were equally good as predictors of the digestibility of gross energy.
Four rumen and abomasum-fistulated Iranian Baluchi sheep in a 4×4 Latin square design as changeover order were used to study the effect of steam treated sugarcane pith (STP) (210 °C,19 bar, 3 min, moisture 70%) on digestibility, rumen passage rate and fermentation by continuous marker infusion technique. The result showed that intake and apparent digestibility of dry matter (DM) are not influenced by treatment, but the high level of pith had the highest digestibility of neutral detergent fiber (NDF) (61%) and acid detergent fiber (ADF) (51%) (P < 0.05). Treatments significantly affected rumen nutrients digestibility (P < 0.05), as digestibility of DM (47 vs. 59.41 g/d), NDF (65 vs. 73%) and ADF (58 vs.70%) was highest in diet containing 120 g/kg pith (STP12) vs. 0.0 g/kg (STP0). Dry matter (50 vs. 42 g/kg DM), crude protein (CP) (131 vs. 108) and NH3-N (172.2 vs. 147.1 mg/l) of abomasum, respectively, for STP0 and STP12, were linearly affected by treatments (P< 0.05). Processing with steam affected dilution rate (DR), rumen turnover time (TT), out flow rate (OFR) and mean retention time (MRT) (P < 0.05). The highest DR (8.35 vs. 7.09) and OFR (0.47 vs. 0.36 L/h) were obtained for STP0 in comparison to STP12. It seems that nutritive value of sugarcane pith as feed for ruminants could be improved by steam treatment.
The aim of the study was to evaluate the effects of fibre source (cassava residue, CR and sweet potato vines, SPV), particle size (1mm and 3mm screen size) and multi-enzyme supplementation (mixture of α-amylase, β-glucanase, cellulase and protease) on growth performance and the coefficient of total tract apparent digestibility (CTTAD) in weaning and growing pigs (Landrace×Yorkshire). The experimental diets were based on maize, fish meal, full fat soybean, soybean meal, soybean oil and CR or SPV. The dietary levels of CR and SPV were 200 and 350g/kg (as fed) in the post-weaning and growing period, respectively. The experiment was arranged according to a 2×2×2 factorial completely randomized design with five replications, and lasted 60 days with two periods: from 30 to 60 days of age (post-weaning) and 60 to 90 days of age (growing). In each period, pigs fed the CR diet had higher CTTAD of dietary components (except for ether extract), average daily gain and lower feed conversion ratio than those fed the SPV diet (P0.05). Addition of the enzyme mixture improved the CTTAD and growth performance in the post-weaning period (P
For the purposes of food evaluation, in vitro digestion/fermentation methods are ethically superior, faster and less expensive than in vivo techniques, whilst still offering a degree of animal–food interaction that pure chemical analysis lacks. One such in vitro fermentation method is the in vitro gas production technique, which utilises the relationship between degradation and fermentative gas production to evaluate the nutritional parameters of foodstuffs. Several different methodologies have been proposed for the gas production technique, each varying in its complexity, shortcomings and benefits. Although the gas production technique has been used almost exclusively with ruminants, it may also be of value for nutritive evaluation of foods for man and other monogastric animals. The benefits of the technique include being able to run large batches simultaneously at low cost, the ability to measure fermentation kinetics of soluble as well as insoluble fractions of food, and the ability to easily make relative comparisons among different foodstuffs. This contribution reviews the in vitro gas production technique, and in vitro hindgut digestion assays generally, for their application in predicting in vitro hindgut digestion and fermentation in humans and monogastric farm animals. It is concluded that currently available in vitro digestion methods of relevance to human food evaluation lack standardisation, in vivo validation and justification to support their specific methodology, and have not been tested with a wide range of fermentative substrates.
A comparative study was performed to determine the digestibility and performance in Zimbabwean indigenous Mukota pigs and exotic Large White pigs fed high fibre diets. Maize cob meal was used as the source of dietary fibre at levels of 0, 100, 200 and 300g/kg. In the digestibility experiment (Experiment 1), four male pigs from each breed were used in a Latin square design. In the feeding trial (Experiment 2), 16 male pigs from each of the two breeds were used in a 2×4 factorial. Polynomial regression analysis was used to determine the relationship between maize cob levels with digestibility of nutrients, feed intake, average daily gain (ADG) and feed conversion ratio (FCR). In Experiment 1, increasing fibre levels in the diets resulted in a linear decrease (P0.05) of maize cob level on feed intake for both Large White and Mukota pigs. The decrease in ADG in the Large White was linear (β=0.0043; R2=0.976) and quadratic in the Mukota pigs (P
Six growing pigs were fitted with a simple T-cannula at the distal ileum. The pigs were given 1 kg of feed twice daily. Three pigs received a grower diet containing 5 g kg−1 chromic oxide and 25 mg kg−1 dysprosium. The markers were withdrawn at the 08:00 h feeding on day 11 of the experimental period. The other three pigs received the diet without the markers. On day 11, at 08:00 h, they were given a single dose of both markers mixed in the diet. The treatments were crossed-over during the second experimental period. The experiment was repeated with the same pigs to measure the rate of passage of these markers in feces. The rate of chromic oxide passage, determined using rate constants, for digesta collected from the distal ileum were similar for the withdrawal and single dose methods. In contrast, the rate of dysprosium passage in digesta measured with the withdrawal method was higher (P < 0.05) than with the single dose method. The rates of passage of both markers, measured in feces, were similar with the two methods. In conclusion, either marker or method can be used to study the relative differences in rate of passage of digesta between diets, although chromic oxide provided more consistent results.
In einem Stoffwechselversuch mit Schweinen wurde der Einfluß von unterschiedlichen Nahrungsfaserträgern im Vergleich zu Stärke auf die Mastleistung und die Energieverwertung untersucht. 20% einer Grundmischung (KO) wurden durch Weizenquellstärke (20%STA), Sojaschalen (20%SO) oder Hirseschalen (20% HI) ersetzt. Insgesamt 16 kastrierte Mastschweine der Rasse Edelschwein wurden bei einem Lebendgewicht (G) von 20.0 kg in Einzelbuchten eingestallt und rationiert gefüttert. Unmittelbar nach der Tötung bei 95.3 kg G erfolgte die Entnahme von Chymusproben aus verschiedenen Abschnitten des Verdauungstraktes.
Im Vergleich zur Variante KO führte die Zulage von 20% Stärke zu derselben täglichen Aufnahme an verdaulicher Energie (VE), hingegen wurden die täglichen Zunahmen um 6% verringert. In der Variante 20%SO konnten im Vergleich zur Variante KO derselbe VE-Gehalt im Futter (Durchschnitt: 15.8 MJ/kg TS) und nahezu dieselbe Mastleistung nachgewiesen werden. In der Variante 20% HI hingegen zeigte sich ein 14% tieferer Gehalt an VE bzw. eine geringere Aufnahme an VE, welche ihrerseits einen geringeren täglichen Zuwachs sowie einen erhöhten Futteraufwand pro kg Zuwachs zur Folge hatte.
Während die Verdaulichkeit der Energie [v(E)] im Dünndarm mit zunehmendem Fasergehalt abnahm, wurde das Ausmaß der vorwiegend mikrobiellen Energieverdauung im Dickdarm nebst dem Gehalt vermehrt durch die Zusammensetzung der Nahrungsfasern bestimmt. Als bedeutendste Einflußfaktoren auf die faecale v(E) erwiesen sich dabei der Gehalt an Lignin und an unlöslichen Hemicellulosen. Der Aufwand an VE pro kg Gewichtszuwachs war bei allen vier Futtervarianten nahezu gleich.
Aus der vorliegenden Untersuchung zeigt sich, daß das Futterrationen für wachsende Schweine ohne Beeinträchtigung der Mastleistung bedeutende Mengen an Nahrungsfasern enthalten können, sofern die unlöslichen Hemicellulosen nicht mit Lignin inkrustiert sind.
A simple batch culture technique utilizing adapted rat caecal flora was used for anaerobic biodegradation of different sugars (glucose and sucrose) and sugar substitutes (sorbitol, Polydextrose® and Palatinit®) in a complex medium (thioglycollate-peptone broth). The cultures were connected to a flow calorimeter in order to quantitate bacterial heat production occurring during incubation. Moreover, increase of biomass and fermentation products (short-chain fatty acids) were measured after each 48-h experiment. If these values exceeded the results obtained from unsupplemented cultures, the calculation of the recovery of the added carbohydrate energy was based on the difference values. The results show that each test substance is converted individually to some extent into heat, biomass and fermentation acids. For all substances no significant variations were revealed regarding specific heat production. However, the specific energy conversion into biomass and metabolites varied. It is concluded that the amount of energy from microbial fermentation process available to the host organism cannot be considered constant. It may depend upon the nature or the quantity of the carbohydrate tested. In addition, the reliability of these in vitro experiments concerning the efficiency of energy conversion of nutrients by intestinal micro-organisms is discussed.
The present study on pigs was conducted to determine the time of passage and the apparent digestibility of the major chemical components of diets containing 0.0%, 5.4% and 11.0 % dietary woodpulp. There were linear decreases in the digestibility of dry matter (r=-0.93), crude protein (r=-0.77), crude fibre (r=-0.73), nitrogen free extract (r=-0.92), ether extract (r=-0.50), crude ash (r=-0.81), acid detergent fibre (r=-0.80) and cell contents (r=-0.86) with increasing levels of dietary woodpulp. The mean retention time decreased linearly (r=-0.80) as the level of crude fibre in the diet increased. The excretion time of the markers was negatively correlated to the daily faecal dry matter output.
1. Large intestine electromyograms were recorded from four pigs receiving successively three diets containing different amounts of fibre (standard cereal diet, milk substitute and milk plus 170 g bran/kg). For each diet the mean retention time of a marker added to one meal was determined. Three occurrences of spontaneous constipation were also studied.
2. Slow waves were observed in the colon only during 10% of the recording time at a frequency of 10.3 ± 1.1/min. Two kinds of spiking activity were recorded on the colon: short spike bursts of 0.5–2 s duration and long spike bursts of approximately 7 s duration. Long spike bursts alone were recorded on the caecum.
3. The mean retention time of the marker was 40 h on the standard diet, 120 h on the milk-substitute diet, and 66 h on the milk plus bran diet.
4. On the standard diet, approximately 1500 colonic long spike bursts were recorded daily and short spike bursts occupied 15% of the recording time. On the milk diet, the number of long spike bursts decreased significantly ( P < 0.01) to 500/d and the short spike bursts increased significantly ( P < 0.05) to take up to 21% of the time. Intermediate values (1100/d and 19%) were observed when bran was added to the milk diet. The lowest values for long spike bursts (300/d) and highest values for short spike bursts (44% of the time) were observed in constipation.
5. It is concluded that long spike bursts are associated with propulsion of intestinal contents and that short spike bursts are non-propulsive.
小腸の3部位にフィステルを装着した子豚を用いて,各消化器官における酸化クロームおよびポリエチレングリコール(PEG)の滞留時間と消化吸収率を測定した.飼料は,離乳用後期飼料(A)と子豚用慣用飼料(B)で,給与量は体重の4%として,毎日一回午前9時に与えた.1. 胃よび十二指腸においては,酸化クロームは乾物と同様の動きを示し,飼料Bの場合,給与量の50%が通過するのに4～7時間を要した.PEGは酸化クロームより速く通過した.2. 小腸における滞留時間は,飼料AとBで,それぞれ,3.40および3.17時間,また,腸管全体では,それぞれ,39.7および28.2時間となり,指標物質間には差が見られなかった.3. 飼料Aの場合,主として大腸における滞留時間が長くなったが,これは,飼料Aの消化性がよいため,飼料Bに比較して腸管内容物の通過量が少ないことに起因すると推察された.4. 酸化クローム法による消化吸収率では,十二指腸までは,乾物,粗蛋白質および灰分で負となり,小腸末端まででは,乾物,粗蛋白質,粗脂肪および可溶性無窒素物における全体の可消化量の80%以上が吸収され,粗せん維は主として大腸で消化吸収された.
Samples of chopped or pelleted grass hay and resulting rumen contents and feces from feeding cattle in changeover trials were sieved, and adequacy of describing results by the log normal distribution was investigated. Geometric mean particle sizes ranged from 235 μ for dissociated pellets to 4,180 μ for chopped hay or log10 means of 2.37 to 3.62. Fitting the cumulative log normal distribution to data from single sievings yielded residual standard deviations less than .311 corresponding to less than 5.1% of the sum of squares for variation in particle size not explained. Fecal samples showed no statistically significant lack of fit, but fewer data pellets and chopped forage did. Nevertheless, the log normal yielded a good practical description in all cases. Sample coefficients of variation of duplicate determinations were less than 14% for mean particle size and less than 8% for standard deviations of particle size. Experimental errors as coefficients of variation include animal variability and were based on means of quadruplicate determinations for rumen content and means of duplicate determinations for feces. These values were less than 6% for three sets of rumen means but were 34% on the fourth. The corresponding statistics for standard deviations of log particle size were less than 10%. Forage sieve data is fitted adequately by normal distributions so that log means and log standard deviations are useful in summarizing results.
A method for measuring the rate of passage of meal through the alimentary tract of pigs by feeding a stained marker is described. The results are given of sixty-four experiments made under standardized conditions on four fattening pigs with live weights ranging from 49·9 to 185·5 lb. and six experiments on a sow weighing 500 lb.
Results were expressed by means of excretion curves. These were sigmoid in shape and from them a value termed R , the mean retention time (hr.) of all the stained particles in the alimentary tract, directly proportional to the area to the left of the curve, was calculated.
In the fattening piga the first appearance of the marker in the faeces occurred 10–24 hr. after feeding, and the mean 5 and 95% excretion times were 21 and 53 hr. respectively. The marker was completely excreted after approximately 80–90 hr. The R value averaged 34·2 hr.
A marker fed at the morning feed (9 a.m.) had earlier 5 and 95% excretion times and the R value was significantly smaller.
There was no statistically significant relationship between the R values and live weight, digestibility of the dry matter of the ration or the dry-matter content of the faeces.
In the sow the 5 and 95% excretion times were 38 and 68 hr. respectively, and the R value averaged 51·1 hr.
Counts of stained particles in the intestines of two of the pigs after slaughter showed that food was delayed mainly in the large intestine.
Photocopy of typescript. Thesis (Ph. D.)--Cornell University, May, 1979. Bibliography: leaves 227-236. Photocopy.
The relationship between diet, pH, and microbial digestion of carbohydrate was examined in 24 pigs fed either a conventional or a low-protein, high-cellulose experimental diet and sacrificed 2, 4, 8, or 12 h after a meal. In animals fed the control diet contents of the cranial half of the stomach demonstrated marked, cyclic fluctuations in pH and high concentrations of organic acids. Contents of the caudal (glandular) half were lower in both pH and organic acid concentration. Despite concentrations of volatile fatty acids (VFAs) as high as 250 meq/liter in the large intestine, the pH remained relatively neutral. The VFA levels remained relatively constant throughout the length of the colon. The VFA transport across isolated gastric and large intestinal mucosa also was examined. All four types of gastric mucosa absorbed and transported VFA at substantial rates. Mucosa of pig cecum and colon transported VFA at much greater rates than gastric mucosa and greater rates than previously determined in equine large intestinal mucosa or even bovine rumen epithelium. Comparison with results of earlier studies in the pony suggested that the higher concentration of VFA in the large intestinal contents of pigs was due to the more rapid rate of digesta passage rather than to less efficient absorption of fatty acids.
Twelve swine were used to assess the movement of fluid and particulate digesta through their gastrointestinal tracts and to determine the diurnal variations in organic acid levels for various segments of the tract. Animals were fed twice daily at 12-hour intervals. Fluid (polyethylene glycol and chromium-labeled ethylenediamine-tetraacetic acid) and particulate markers (2 mm OD, and 2 mm and 1 and 2 cm long) were administration of markers. The gastrointestinal tract was divided into 12 segments for measurements of markers, pH, volatile fatty acids (VFA), and lactic acid (LA) contents. The data indicated a rapid evacuation of the fluid and the smaller particles from the stomach and their relatively rapid passage through the small intestine and cecum. There was, however, prolonged retention of both fluid and particulate markers first in the ascending and then in the descending colon. Larger particles (2 cm) were retained in the stomach throughout much of the 60-hour experimental period. LA levels were observed 8 hours postfeeding. The highest levels of VFA in gastric contents averaged 20 mmoles/liter. Gastrointestinal pH values showed significant changes with time postfeeding only within the stomach, where they did not reflect the changes in LA of VFA concentrations. VFA constituted 92% of the organic acids present in the large intestine. Their concentrations varied markedly with time (150-230 mmoles/liter), but the VFA at all times constituted the major anions in the large intestinal contents. The results demonstrated that digesta can be retained for prolonged periods of time in that swine stomach and colon. The high concentrations of organic acids also indicated that substantial degrees of microbial digestion of carbohydrates occurred at both sites.
The rates of passage of markers of fluid and particulate digesta through the sheep alimentary tract have been described mathematically in single injection experiments by analysing the concentration curves of marker excretion in faecal dry matter and then predicting these concentrations by means of an equation containing two exponential terms. Three components related to this equation are a transit time for digesta in the intestines, a half time of marker in the reticulo rumen and a half time tentatively associated with the passage of marker through the caecum and proximal colon. With this approach no surgical interference with an animal is required to obtain meaningful information about gut function. Abomasal cannulation did not affect the rate of passage of 51Cr EDTA through the gut. The mean half times for 51Cr EDTA in the reticulo rumen and hind gut, respectively, were 646 and 236 for a roughage diet and 890 and 607 min for a diet consisting mainly of wheat grain, both diets providing approximately the same amounts of digestible dry matter. These results indicated that the changes in half times were proportionately much greater in the caecum and proximal colon than in the reticulo rumen. The mean transit time of marker through the digestive tract also increased from 721 to 1345 min when the concentrate diet was given. The complex of chromium 51 with EDTA was excreted faster in faeces than cerium 144 praseodymium 144 when both were given together as a single injection into the reticulo rumen. This was caused mainly by differential rates of elimination of water and particulate matter from the reticulo rumen.
Sheep were given 800 g lucerne chaff/d and the mean half times of cerium 144 praseo dymium 144 and the complex of chromium 51 with EDTA were 811 and 604 min in the reticulorumen, 37 and 17 min in the abomasum and 413 and 406 min in the caecum and proximal colon respectively. The average time available for digestion and absorption in the abomasum was therefore very short relative to that in the other two organs. The half times of the markers also indicated that particulate matter and water had different rates of turn over in the reticulorumen and abomasum but not in the caecum and proximal colon. Evidence is presented which suggests imperfect mixing of the digesta in the caecum and proximal colon.
Fiber sources were fed to 24 men to evaluate the effect of fiber on large intestinal microflora. The diets were low fiber basal or the basal diet supplemented with coarse bran, fine bran, cabbage, or cellulose (Solka floc). Twelve subjects (Group 1) were fed all fiber sources using a latin square design with 2-week experimental periods followed by a 3-week period on the basal diet. Group 2 made one diet change after the first experimental period, then remained on that diet throughout the experiment; during the last period their fiber intake was double (to approximately 26 g/day). A microbial culture system was utilized with fecal microflora to measure cell wall indigestibility and volatile fatty acid (VFA) production. Volatile fatty acids were also measured in fresh feces. The in vitro substrates were alfalfa, coarse bran, cabbage, or cellulose. In this system, dietary fiber had a significant (P less than .05) effect on resultant cell wall indigestibility and VFA level. Previous diet in group 1 subjects significantly (P less than .05) affected in vitro VFA. In groups 2 significant (P less than .05) period and subject effect were present for the in vitro VFA data. The VFA concentrations in feces of humans were significantly affected by the fiber consumed.
A new liquid marker, cobalt-ethylenediamine tetraacetic acid (EDTA), and two solid markers, chromium (Cr) and cerium (Ce) mordanted plant cell walls, were investigated. Synthesis and methods of analysis are described for the markers. The Cr- and Ce-cell wall complexes were tested for stability to EDTA, hydrochloric acid and rumen microorganisms. Plant cell walls were rendered indigestible by mordanting with Cr and 98% of the marker remained on the fibre after a simulated sequence (in vitro) of digestion. Ce-mordanted cell walls were 35% digestible in vitro using a rumen culture, and 56% of the marker could be washed off the remaining fibre. Treatment with EDTA removed all Ce and 15% of the Cr. Hydrochloric acid (0.01M) had a negligible effect on the removal of Cr from the cell walls, whereas 0.1M acid removed, on average, 10% of the marker. Losses of Cr from the mordant may be related to the quality of the preparation. Co-EDTA was found to be comparable to Cr-EDTA. The urinary excretion of Cr and Co was 2–3% in most animals except in rabbits, which excreted as much as 30% of the liquid markers in the urine.
A User's Guide to SAS 76
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The Physiology of Domestic Animals
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The Rumen and Its Microbes
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Alimentary kinetics of pigs fed three meals daily
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Gastrointestinal transit in the pig: Measurement using radioactive lanthanides and comparison with sheep
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